Telephone-exchange system



C. B. FOWLER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED SEPT.23, 1919.

1,387,250, Patented Aug. 9,1921.

by W m y.

UNITED STATES PIA-TENT OFFICE.

CLARENCE B. FOWLER, OF NEW YORK, N. Y., ASSIGNOR WESTERN ELECTRIC COM-PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

l Specification of Letters Patent; 7

Patented'Aug. 9, 1921 Application filed September 23, 191a serial No.325,609.

To all whom it may concern:

Be it known that I, CLARENCE a. citizen of the United States, residin atNew York, in the county of New'York, State of New York,',have inventedcertain new and useful Improvements in Telephone-EX- In some telephoneexchange systems it is I desirable that the subscriber may be enabled tocontrol the line signaling device, as well as the supervisory signalingdevice, of a link circuit connected with the line. This feature isespecially desirable in case the subscriber desires to recall theoperator.

It is the object of this invention .to provide an improved system ofsignaling between the subscriber and the operator, whereby it ispossible for the subscriberv to control the line signal independently ofthe connection of a link circuit with the associated line. v

To attain this object in accordance with a feature of the invention,means is provided associated with a line circuit whereby the connectionof a link circuit with the line renders the link circuit supervisorysignaling device responsiveto a subsequent deenergization of the linerelay, and the line signaling device responsive to a subsequentenergization-of such relay without altering the condition of theinterconnected talking conductors. c

This and other features of the invention not specifically mentionedabove-will be apparent from the following specification and the annexeddrawing,wl1ich shows diagrammatically a telephone line circuit embodyingthe invention and a. portion of an operators cord circuit forcooperationtherewith.

In the drawing, a line A: connects a subscribers station of any usualtype with a central office and terminates thereat in the usual jack 1. Aline lamp 3 associated with the jack 1 is controlled by a line relay 4.A cord circuitB, of any usual type, provided with a supervisorysignaling lamp5 and an operators listenin' key 6 terminates in a plug 2fOfCOllIlGCtlOIl with the line A, only suliicient portions of suchcord-circuit being shown to properlyillustrate the invention. A doublewound sleeve relay 7 and a slow B. FOWLER,

release relay 8 cooperate with the line relay 4 to control thesupervisory signaling lamp 5 and the line lamp 3 duringa connection ofthe link circuit B with the line circuit A.

It is thought that the invention may be more fully comprehended from thefollowing description of the operation of the system, shown on thedrawing. 7

The subscriber at the station associated with the line A initiatesa callin the usual manner by removing the telephone receiver thereat, therebyoperating relay 4 over a circuit established from battery through theright-hand winding of relay 4, one line conductor, the apparatus at thesubscribers station, the other line conductor and the lefthand windingof relay 4 to ground. Lamp 3 is lighted over a circuitestablished frombattery through lamp 3,;the normal contact of relay 7 and the alternatecontact of relay 4 to ground. In response to the lighting of lamp 3, theoperator inserts plug 2 of link 'circuit B into jack 1 oflin'e circuitA, thereby operating relay 7 over a circuit established from batterythrough supervisory lamp 5, sleevecontacts of plug 2 and jack 1, andboth windings of relay 7 to ground. The high resistance of such circuitprevents thelighting oflamp The opening of the' normal contact of relay7 extinguishes linelamp 8.

The number of the line desired may then be obtained by the operator bythe actuation of the listening key 6, and the connection may beestablished with the calledline in the usual manner.

Upon completion of the conversation, the restoration of the receiver atthe subscribers stationv associated withthe line A releases relay 4:,thereupon operating slow-release relay'8 over a circuit extending frombattery v through the winding of relay'8,.,the normal contact of relay 4and the alternate contact of relay 7 to ground. Relay 8 thereupon locksin an operated conditionover a circuit established. from battery throughthe winding and the middle alternate contact of relay 8 andthe alternatecontact of relay7 to ground. The closure of the right-hand contact ofrelay 8 short-circuits the high resistance left-hand winding of relay 7,thereby sufiiciently reducing the resistance in thecircuit containingsupervisory lamp 5 to permit the lighting of such lamp to serve. as adisconnect signal. Due to the,

locking of relay 8 under the control of relay 7, the lamp 5 remainslighted while the plug 2 remains in the ack l, but the removal of theplug, in response to the disconnect signal, restores all apparatus tothe normal condition.

However, in case the subscriber desires to initiate a recall, theremoval of the receiver from the switchhook, while the plug 2 re mainsin the. jack 1, causes the reoperation of relay 4 lighting the line lamp3 over a circuit extending from battery through lamp 3, the left-handcontact of relay 8 and the alternate contact of relay 4 to ground. The

operator upon observing such recall signal, may actuate the listeningkey 6 and upon ascertaining that the subscriber desires anotherconnection removes the plug 2 from the jack 1, thereby restoring theapparatus vention the subscriber may recall the opera tor during thecontinuance of a connection by the relighting of the line lampsupplementing the lighting of the supervisory lamp of the cord circuit.

What is claimed is:

1. In a telephone exchange system, a line circuit, a link circuit forconnection therewith, a signalingdevice associatedwith the line circuit,a signaling device associated with the link circuit, a relay associatedwith the line circuit, a second relay controlled by the first relay,alocking winding for said second relay, means for causing the secondrelay to lock in the operated position through its locking Winding tomaintain the link circuit signaling device in an operated conditionduring the continuance of the connection, and means for controlling bythe joint action of both relays both signal devices.

2. In a telephone exchange system, a line circuit, a link circuit forconnection therewith to establish a talking circuit including conductorsof the interconnected line and link circuits, a relay associated withthe line circuit, a signaling device responsive to the energization ofthe relay, a signaling device for the link circuit, means responsive tothe connection of the link circuit with the line circuit to restore thefirst mentioned signaling device, means responsive to the deenergizationof the relay to operate the link circuit signaling device, and means.independent of the talking circuit and responsive to a subsequentenergization of the relay during the continuance of the connection toreoperate the line signaling device.

naling device,

3. In a telephone exchange system, a line circuit, a link circuit forconnection therewith, a relay associated with theline circuit, asignaling device responsive to the energization of the relay, asignaling device for the link circuit. means responsive to theconnection of the link circuit with the line circuit to restore thesignaling device associated with the line circuit, means responsive tothe deenergization of the relay to operate the. signaling deviceassociated with the link circuit, means responsive to a subse sequentenergization of the relay during the continuance of the connection toreoperate the line signaling device and means for maintaining saidsupervisory signaling device in an operated condition during thecontinuance of the connection.

l. Ina telephone exchange system, a line circuit, a link circuit forconnection therewith, a signaling device associated with the linecircuit, a signaling device associated with the link circuit,subscriberand operator controlled means for operating both signaling devicesduring the connection of the link circuit with the line circuit, and

means for maintaining said link circuit signaling device in an operatedcondition in-- dependently of the subscriber controlled means.

5. In a telephone exchange system, a line circuit, a link circuit forconnection therewith, a relay associated with the line circuit, asupervisory signaling device for the link circuit, a high resistancecircuit completed therefor upon the connection of the link circuit withthe line circuit, means responsive to a denergization of the relay toreduce the resistance of the high resistance circuit thereby causing theoperation of the supervisory signaling device, and means for maintainingthe supervisory signaling device in an operated condition independentlyof subsequent energizations of the relay.

6. In a telephone exchange system, a line circuit, a link circuit forconnection therewith, arelay for the line circuit, a signaling devicecontrolled therebyra supervisory signaling device for the link circuit,asecond relay operating in response to the connection of thelink circuitwith the line circuit to restore the line signaling device, and a thirdrelay operating upon the deenergization of the first mentioned relayandlocking under control of the second relay to op- .erate thesupervisory "signaling device, and a circuit for the line signalingdevice prepared by said third relay and completed upon a subsequentenergization of the first mentioned relay to reoperate the line sig- 7.In a telephone exchange system, a line circuit, a relay associatedtherewitln'a signaling device responsive to the energization of therelay, a link circuit for connection with the line circuit, meansresponsive to the connection of the link circuit With the line circuitto remove the line signaling device from the control of the relay, andmeans responsive to the deenergization of the relay to return the linesignaling device to the control of the relay.

8. In a telephone exchange system, a subscribers line circuit, asignaling device therefor, a link circuit for connection With the linecircuit, a signaling device therefor,

subscriber controlled means for operating both devices during aconnection of the link circuit with the line circuit and operatorcontrolled means for maintaining the link circuit signaling device in anoperated con dition during the continuance of such connection.

In Witness whereof, I hereunto subscribe my name this 19th day ofSeptember, A. D. 1919.

CLARENCE B. FOlVLER.

